Apparatus for stretcher leveling strips



Dec. 16, 1947. STONE 2,432,828

APPARATUS FOR STRETCHER LEVELING STRIPS Filed July 1, 1959 2Sheets-Sheet 1 ATTORNEY Dec. 16, 1947. M. D. STONE APPARATUS FORSTRETCHERLEVELiNG STRIPS 2 Sheets-Sheet 2 Filed July 1, 1939 AfioRNEYPatented Dec. 16, 1947 APPARATUS FOR STRETCHER LEVELING STRIPS MorrisDenor Stone, Pittsburgh; Pa., assignor to United Engineering and FoundryCompany,

Pittsburgh, Pa.

Application July 1, 1939, Serial No. 282,457

3 Claims. (Cl. 205-1) This invention relates to the flattening of metalstrip material, and more particularly to an apaparatus for stretchingand leveling continuously moving metal strip.

It is among the objects of this invention to provide an apparatus ofthis character which does not require the use of leveling rollers or thelike in its operation and is at the same time capable of both workingand flattening the strip and of doing so at relatively high speeds.Another object is the provision of apparatus for continuously coldworking and leveling strip which is eflicient in operation, simple inconstruction and adapted to be maintained at comparatively small cost.

In accordance with this invention metal strip is continuously acted uponby a pair of spaced tension units which are either operated at differentspeeds or are adapted to tend to operate in opposite directions but areso controlled that the strip is advanced after being stretched a uniformamount which is sufllcient to level or flatten it. More particularly,the strip is fed between rotatable drag tension means and pull tensionmeans which engage it and apply tension in excess of its elastic limitto the intervening portion of the strip. Tension is also preferablyapplied to the strip before and after it engages the drag and pulltension means, although this is not necessary where such meansfrictionally grip the strip sufficiently to prevent slippage. Means areprovided for varying the speed of one or both of the tension means so asto obtain the desired tension on the strip and maintain it constant, orto obtain a uniform amount of stretchmg per lineal unit. The strip ispreferably caused to travel through a zig-zag or reverse bend path as itenters the stretching zone in order to work the metal of the strip andthereby promote stretching. Before the strip reaches the drag tensionmeans it may also be subjected to rather sharp reverse bends to coldwork its surfaces so as to prevent the strip from developing stretcherstrains. In one form of the invention the strip is threaded into theflattening apparatus while the stretching rollers are in a position inwhich they make the threading very easy, after which they are moved intooperative position.

The invention is illustrated in the accompanying drawings in which Fig.1 is a plan view, partly in section, of one embodiment; Fig. 2 is avertical two tension units applying sufllcient tension to the stripbetween them to stretch it beyond its elastic limit. The two tensionunits are consection of Fig. 1 taken through the center of the structedsubstantially alike, each one including a roller 6 the necks of whichare journaled in bearings 1 supported by laterally spaced side frames 8.Rotatably mounted on each roller neck between its body and its bearingis a large toothed disc 9 which is provided at one side of its axis witha bearing. for receiving one neck of an outer roller l2. The latterroller is driven by the roller 6 by means of gears l3 mounted on theirnecks. To rotate the toothed discs so that the roller I2 can be swunglaterally in an arcuate path around the fixed roller for a purpose aboutto be described, the disc teeth mesh with pinions ll keyed on a shaft l6journaled in the side frames 8 and turned by a motor II.

This mounting of the rollers permits the accomplishment of one of thefeatures of this invention; namely, easy initial threading of the stripthrough this apparatus. Accordingly, when it is desired to prepare thisapparatus for operation the discs 9 are first rotated by pinions I toswing the outer rollers H of the two tension units around the fixedrollers 6 to the broken line positions shown in Fig. 2, where they areabove rollers 6. The leadin end of the strip from the uncoiler I is thendrawn through each set of rollers and connected to the uncoiler 4. Thisthreading of the strip is very easy because each pair of rollers isspaced apart and forms a wide horizontal pass through which the strippasses in a generally straight line from the uncoiler. The discs 9 arethen rotated to swing rollers I! outwardly toward the adjacent reels andthen inwardly and upwardly to the positions shown in full lines in Fig.2. This movement causes rollers I! to loop the strip beneath the portionbetween rollers Ii so that it will travel around two reverse bends as itpasses through each tension unit. It also causes the strip to engageover half of the surface of each roller, whereby it is frictionallygripped by the rollers without being pinched between them. Thisfrictional grip is increased to the point where there is no danger ofslippage, and the strip between the tension units and adjacent reels isheld taut, by applying tension to the strip by means of the reels.

After the apparatus has thus been prepared for operation, the variousrollers and reels are set in rotation to pass the strip through thetension units from the uncoiler to the coiler. As indicated above, theuncoiler I is rotated at a slower ing it so that it will function as agenerator when the strip is pulled from the uncoiler. Although thetension thus put on the strip between un- 3 coiler and drag tension unitis material for the reasons previouslymentioned, it is not sufficient tostretch the strip beyond its elastic limit. On the other hand, the pulltension rollers are driven by a motor 23 at a peripheral speedsufilciently in excess of that of the otler set of rollers, connected toa motor 22 operated in the same manmay be maintained uniform by asuitable loop tension control 21 of conventional type engaging the stripbetween the tension units.

On the other hand the tension may be automatically varied by themechanical means shown in Fig. 3 in order to efiect a uniform amount ofstretching per lineal unit. In this embodiment of the invention the neckof drag tension roller 6 is provided with a bevel gear 3| and the rolleris driven by an electric motor 32. Meshing with this gear is a bevelgear 33 mounted on one end of a shaft 34 the opposite end of whichcarries a bevel gear 36 disposed in a differential cage 31. At theopposite side of the cage is a bevel gear 38 mounted on one end of ashaft 39 carrying at its outer end a bevel gear 4i meshing with asimilar gear 42 mounted on the end of the neck of pull tension roller 6.Meshing with the two bevel gears in the differential cage are oppositelydisposed idler gears 43, and the entire cage is rotated by a ring gear44 encircling it and meshing with a pinion 46 driven by a variable speedmotor 41.

With the drag tension unit motor 32 operating at a predetermined speed,the bevel gear 36 in the differential is rotated at a uniform rate. Thedifferential motor 41 is driven faster than this gear, and thereforecauses the opposite gear 38 to rotate faster likewise. Thus, the pulltension rollers are driven at higher speed than the drag tensionrollers. The amount of elongation of the strip is automaticallyindicated by the electrical speed ratio meter 48 connected with the twotension units.

It will thus be seen that the apparatus described thus far is relativelysimple in construction and operation. The mounting of the outer tensionrollers l2 greatly facilitates threading of the strip through theapparatus before it is set in operation. The reverse bending of thestrip as it passes over the rollers in the drag tension unit works themetal sufficiently to promote stretching. Furthermore, as the stripmerely passes over instead of forming coils on the tension rollers 6between which it is stretched, the thick center of strip that is thinnerat its edges does not become cumulative on these rollers and therebycause the strip to be bowed transversely instead of leveled.

On the other hand, if the strip is of substantially the same thicknessthroughout its width, the embodiment disclosed in Fig. 4 may be used.The tension rollers have been entirely omitted from this embodiment, andtension is applied to the strip so ely by the drag and pull of theuncoiler 5| and the coiler 52. The coiler is driven by a motor 53 at aperipheral speed sufllciently in excess of the speed of the uncoiler toapply 4 sufiicient tension to the strip to stretch it beyond its elasticlimit, and thereby level it. The tension on the strip may be controlledin a suitable automatic manner, such as previously described inconnection with Figs. 1 and 3.

In the modification shown in Fig. 5 the drag tension rollers 60 and thepull tension rollers 6| are rotataby mounted in fixed position and eachone is driven by a separate motor 62 which may be automaticallycontrolled to function in the manner described in the precedingembodiments. The separate drive for each roller makes it unnecessarythat the rollers in each set have diameters which are exactly the same.This is important because it is diiricult to keep the rollers of equaldiameter, especially after they have been reground. The separate drivefor each roller does away with this trouble and expense, for the motorfor each roller drives that roller at a speed that compensates for thedifference in diameter between it and the adjacent roller.

' The rollers in each set are preferably mounted one above the other.and the strip 63 passes through each set preferably by extending acrossthe top of the upper roller, back between both rollers, and across thebottom of the lower roller. This gives the strip a zig-zag path oftravel throu h each tension unit and causes it to frictionally engage amaterial portion of the surface area of each roler. To increase the gripof the rollers on the strip, a billy roll 64 presses the strip downagainst the top of each upper roller, and the coiler 66 and uncoiler 61are driven at such speeds by their motors 6B and 69. respectively, as toapply tel $1011 to the strip which is material but insufficienttostretch it beyond its elastic limit. The pull tension rollers 6| aredriven faster than the drag tension rollers 60 so that the stripbetwe'en them will be stretcned beyond its elastic limit in order toflatten it. On the other hand, the speeds of the various rollers may beeffected as in the first embodiment. Also it is not necessary torestrict each tension unit to these rollers, as shown, because it may bedesirable to use four or more if the material is heavy and high tensionis required. Also, if sufiiclent rollers are provided to avoid anypossibility of slippage in case the tension exerted by the coiler anduncoiler is eliminated. then this machine may be used in any continuousprocessing line.

Ano her feature of this embodiment is the use of a plurality of smallbacked-up bending rolls 1| mounted between the uncoiler and the dragtension rollers. As the stri passes between these bending rolls it isreversely bent rather sharply whereby its surfaces are cold workedsufliciently to prevent stretcher strains developing during thestretching of the strip between the two sets of tension rollers. Thisfeature is especially advantageous with strip that has been softannealed.

According to the provisions or the patent statutes, I have illustratedand described what I now consider to be the preferred embodiments of myinvention. However, I wish to have it understood that, within the scopeof the appended claims, the invention may be practiced otherwise than asspecifically shown and described.

I claim:

1. Stretcher-leveler apparatus for continuously-moving strip material,comprising a drag tension unit and a pull tension unit, each of saidunits including a roller j ournaled in fixed position. a roller adaptedto be adjusted laterally in an arcuate path around said fixed roller,and a power element for driving said rollers.

2. Stretcher-leveler apparatus for continuously-moving strip material,comprising a drag tension unit and a pull tension unit, each of saidunits including a roller journaled in fixed position, a power elementfor driving said roller, a second roller journaled beside said fixedroller, a power element for adjusting said second roller in an arcuatepath around said fixed roller, and a power element for driving thesecond roller from said fixed roller.

3. Stretcher-leveler apparatus for continuously-moving strip material,comprising a drag tension unit and a pull tension unit, each of saidunits including a roller journaled in fixed position, a rotatable membermounted at each end of REFERENCES CITED The following references are ofrecord in the file of this patent:

Number UNITED STATES PATENTS Name Date Reese May 18, 1880 Conklin June19, 1906 Scott June 17, 1913 Cross May 27, 1919 Duston Sept. 14, 1920McBain Oct. 4, 1932 McBain Aug. 22, 1933 Coryell Jan. 9, 1934 Nieman May12, 1936 Hanson Nov. 3, 1936 McChesney Dec. 20, 1938 Montgomery Apr. 11,1939 Lynch May 23, 1939 Sendzimir Aug. 15, 1939 Moore 0ct. 17, 1939Thomas Jan. 30, 1940 Hudson Feb. 20, 1940 FOREIGN PATENTS Country DateNmnber Great Britain Sept. 14,1936

